This invention relates to a silver halide photographic paper and especially it relates to a silver halide photographic paper which includes a silver halide developing agent and has a hydrophilic colloid backcoating layer on the back side and which is free from blocking between the emulsion surface and the backcoating layer when stored in the form of a roll or a stack and is reduced in haze on the surface of the emulsion layer.
Hitherto, baryta paper has been used as a support for photographic paper, but recently, for the purpose of rapid photographic treatment there has been used a photographic paper coated with a water resistant resin on both sides. Photographic papers having such resin coated paper as a support have a mirror surface (smooth and gloss surface), a matte surface, or a silky surface in accordance with the state of the side to be coated with an emulsion (which will be called "front side" hereinafter). On the other hand, the side of a support which is opposite to the side to be coated with emulsion has a matte surface of various types (This side will be called "back side" hereinafter.).
When photographic papers having a front side of mirror-like surface are stored in the form of a roll or a stack, the emulsion surface of front side is kept in contact with back side. On the back side, there is usually provided a hydrophilic colloid layer, which often causes blocking with the emulsion surface. Especially, those photographic papers which contain silver halide developing agent in their emulsion layer for rapid development further tend to cause blocking because the developing agent hinders hardening of the emulsion layer. This tendency is further promoted when the photographic papers are heated by mill rolls after coating of emulsion layer. Those photographic papers which have suffered from blocking have streak-like haze (the state of lower gloss) on the surface to result in conspicuous reduction in commercial value as photographic paper. In an extreme case, the backcoating layer on the back side and the emulsion layer completely stick to each other and they cannot be separated from each other.